Coordinated control of mRNA and rRNA processing regulates early mammalian embryogenesis [RNA-Seq]

Stem cells are regulated by transcriptional networks controlling pluripotency and differentiation. How basic cellular processes like splicing or protein synthesis regulate stem cell function is less well understood. Here, we show that the RNA binding protein HTATSF1 controls protein synthesis by controlling several independent RNA processing steps during ribosome biogenesis. In a complex with ribosomal RNA transcription and processing factors, HTATSF1 regulates ribosomal RNA abundance. By binding to the U2snRNP complex, HTATSF1 also controls intron removal specifically in ribosomal protein transcripts. HTATSF1-mediated control of protein synthesis is essential for the transition from the naïve pre-implantation epiblast to the primed post-implantation epiblast, a stage of low protein synthesis levels, and during further differentiation towards neuroectoderm. Our results identify coordinated regulation of ribosomal RNA and protein biosynthesis by HTATSF1 as an essential mechanism to mediate protein synthesis control during early stages of mammalian embryogenesis.